公开(公告)号：DE2645918A1

公开(公告)日：1978-04-13

申请号：DE2645918

申请日：1976-10-12

Applicant: BASF AG

Inventor： DEUSCHEL WALTER DIPL CHEM DR ,  LAY PETER N DIPL ING

IPC: C08F6/00 ,  C08F6/16

Abstract: Extraction of residual monomers from dispersions or suspensions of polymerised materials, and esp. vinyl chloride from PVC prepd. by suspension or emulsion polymerisation comprises subjecting the dispersion or suspension of the polymerised product to a usual extraction to remove unpolymerised vinyl chloride, and when the major portion of residual monomer has been removed from the reactor, i.e. when the effective pressure in the reactor is reduced to 1-4 bars, and without interruption of the extraction, the reactor contents are heated with superheated steam to a final temp. of 70-100 degrees C pref. 80-95 degrees C the increase in temp being >=0.5 degree C/min. pref. 1-2 degrees C/min. so as to attain the desired final temp. at the moment when the effective press in the reactor returns towards 1 bar. The gaseous products comprising steam and vinyl chloride are then removed from the reactor at a pressure corresponding to the vapour press. of water at the final temp. No thermal deterioration of the polymer is caused. Partic. good results are obtd. with vinyl chloride homopolymers and its copolymers with =30% of other monomers e.g. vinyl acetate, vinyl propionate or vinylidene chloride.